The present invention relates to a loading/unloading mechanism for loading and unloading a magnetic head mounted on a magnetic disk drive for recording data in a magnetic recording medium.
It has been customary to start and stop the operation of a magnetic disk drive by a contact start/stop (CSS) system. The CSS system starts and stops the operation of the disk drive while maintaining a magnetic disk and a flying head slider in contact with each other. The prerequisite to the CSS system is that the surface of the medium be roughened to a degree sufficient to prevent the head slider and medium from sticking together while the disk drive is not in operation. This brings about a problem that the head slider has to fly more than necessary, obstructing the increase in recording density. In addition, friction particular to the CSS system and dust particles ascribable to the friction cannot be eliminated.
Moreover, to meet the increasing recording density, access speed and transfer rate, attempts for reducing the flying amount of the head slider are under way. This in turn requires the pressure generating surface of the head slider and the surface of the magnetic disk to be smoother, aggravating the probability of head crush ascribable to the above-mentioned dust particles and the adhesion of disk and head slider.
On the other hand, with a miniature magnetic disk drive mounted on, for example, a lap top computer, there is a tendency that the disk drive is automatically damaged when a predetermined period of time expires without any input for the purpose of saving power. Hence, there is an increasing demand for a CSS resistive characteristics sufficient to meet the increase in the frequency of CSS operation. Another requisite for the disk drive is high resistivity to impacts. In the CSS system, intense impacts would damage the disk, head slider, head, etc.
In light of the above, a loading/unloading mechanism has been developed which causes the disk drive to start and stop operation without the flying head slider contacting the magnetic disk. A loading/unloading mechanism of the type using a ramp mechanism causes the ramp mechanism to support part of a suspension mechanism while the disk drive is out of operation. The suspension mechanism is so designed as to exert a predetermined load on a flying head slider when the head slider is held in a usual flying state. However, when the suspension mechanism is supported by the ramp mechanism, the former exerts a heavier load on the latter.
When the head is to be loaded on the medium, a positioner actuator exerts a force on the suspension mechanism which is greater than the static frictional force ascribable to the contact load, aggravating the power consumption. In the event of loading, since the position of the head slider noticeably influences the contact/noncontact of the head slider with the medium, the speed of the positioner actuator has to be controlled to prevent undesirable oscillations from occurring in the suspension mechanism. However, controlling the speed of the positioner actuator with accuracy is extremely difficult since the static frictional force is susceptible to the environment.